• MESO: Mesoscale Discussion 2229

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Mon Nov 18 07:26:05 2024
    ACUS11 KWNS 180725
    SWOMCD
    SPC MCD 180725=20
    OKZ000-TXZ000-180930-

    Mesoscale Discussion 2229
    NWS Storm Prediction Center Norman OK
    0125 AM CST Mon Nov 18 2024

    Areas affected...much of northwestern Texas into southwestern
    Oklahoma

    Concerning...Severe potential...Watch likely=20

    Valid 180725Z - 180930Z

    Probability of Watch Issuance...80 percent

    SUMMARY...Potential for damaging wind gusts and perhaps a few
    tornadoes may begin to increase with an evolving squall line
    accelerating northeast of the Texas South Plains through much of
    northwestern Texas and southwestern Oklahoma by 3-5 AM CDT.

    DISCUSSION...Downstream of a 90+ kt 500 mb jet streak beginning to
    nose northeast of the Texas Big Bend into the Pecos Valley, strong
    forcing for ascent continues to aid the evolution of a squall line
    in advance of a deepening surface low now near/southwest of Lubbock. Instability is still rather weak in the presence of thermodynamic
    profiles characterized by modest mid-level lapse rates, but weak
    low-level lapse rates and modest moisture. However, low-level and
    deep-layer shear is strong, and an ill-defined meso-beta scale
    mid-level cyclonic circulation is now progressing northeast of
    Lubbock.=20=20

    A number of better defined meso-gamma scale cyclonic circulations
    are evident along the line, which has been surging northeastward
    around 30 kt, to the northeast of the mid-level circulation. This
    appears likely to propagate into the Altus OK vicinity through
    09-11Z, with the southern flank of the line progressing across the
    Abilene TX vicinity.
    =20
    In response to the deepening surface troughing, a gradual
    north-northwestward advection of mid 60s to near 70F surface dew
    points toward the upstream squall line will gradually contribute to
    somewhat more unstable updraft inflow. This may also contribute to
    a boundary-layer at least marginally more supportive of downward
    momentum transfer to the surface and potential for tornadoes, as
    low-level shear intensifies beneath an 850 mb jet forecast to
    strengthen in excess of 50 kt.

    ..Kerr/Gleason.. 11/18/2024

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!-sqgINu_D0vLftfZfv0-T_hdnuxH6G2sI4rqJUAiG1sxnN89WQfTWtrahsTisT2JG12zAQoUz= PrZhamWpzs80TQeMxU$ for graphic product...

    ATTN...WFO...FWD...OUN...SJT...LUB...AMA...MAF...

    LAT...LON 33610035 34130064 35169968 35239810 34159800 32049873
    31479966 31470050 32160084 33610035=20


    =3D =3D =3D
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  • From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Mon Nov 18 08:03:05 2024
    ACUS11 KWNS 180803
    SWOMCD
    SPC MCD 180802 COR
    OKZ000-TXZ000-180930-

    Mesoscale Discussion 2229
    NWS Storm Prediction Center Norman OK
    0202 AM CST Mon Nov 18 2024

    Areas affected...much of northwestern Texas into southwestern
    Oklahoma

    Concerning...Severe potential...Watch likely=20

    Valid 180802Z - 180930Z

    CORRECTED FOR TIME REFERENCE TO CST

    Probability of Watch Issuance...80 percent

    SUMMARY...Potential for damaging wind gusts and perhaps a few
    tornadoes may begin to increase with an evolving squall line
    accelerating northeast of the Texas South Plains through much of
    northwestern Texas and southwestern Oklahoma by 3-5 AM CST.

    DISCUSSION...Downstream of a 90+ kt 500 mb jet streak beginning to
    nose northeast of the Texas Big Bend into the Pecos Valley, strong
    forcing for ascent continues to aid the evolution of a squall line
    in advance of a deepening surface low now near/southwest of Lubbock. Instability is still rather weak in the presence of thermodynamic
    profiles characterized by modest mid-level lapse rates, but weak
    low-level lapse rates and modest moisture. However, low-level and
    deep-layer shear is strong, and an ill-defined meso-beta scale
    mid-level cyclonic circulation is now progressing northeast of
    Lubbock.=20=20

    A number of better defined meso-gamma scale cyclonic circulations
    are evident along the line, which has been surging northeastward
    around 30 kt, to the northeast of the mid-level circulation. This
    appears likely to propagate into the Altus OK vicinity through
    09-11Z, with the southern flank of the line progressing across the
    Abilene TX vicinity.
    =20
    In response to the deepening surface troughing, a gradual
    north-northwestward advection of mid 60s to near 70F surface dew
    points toward the upstream squall line will gradually contribute to
    somewhat more unstable updraft inflow. This may also contribute to
    a boundary-layer at least marginally more supportive of downward
    momentum transfer to the surface and potential for tornadoes, as
    low-level shear intensifies beneath an 850 mb jet forecast to
    strengthen in excess of 50 kt.

    ..Kerr/Gleason.. 11/18/2024

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!-l_NNB_qckDrSPg-oIPr3-9-HAPwUtEioGtsKWpIH9Nsx-ReqWpcMoCrk1yaTCXBexsGsnbx5= ngyec87TEUJgfr9guI$ for graphic product...

    ATTN...WFO...FWD...OUN...SJT...LUB...AMA...MAF...

    LAT...LON 33610035 34130064 35169968 35239810 34159800 32049873
    31479966 31470050 32160084 33610035=20


    =3D =3D =3D
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